CCL2 and Parkinson disease: In the present study, we provide evidence that DA neurons loss and hypokinesis were associated with activation of microglia in PD mouse model, similar observations in cultured microglia suggested that activation of microglia by MPP+ enhanced the production of IFN-γ, TNF-α, IL-1β, IL-6 and induced the additional M1 microglia, at the same time, high level of main histocompatibility complex-II (MHC-II), monocyte chemotactic factor-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α) were also detected.